Drum Rotor Bearing Support for Deflection Control in Gas Turbines
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Solution Overview
Problem
Rotating drum rotors in gas turbine engines experience high deflection at their free ends during bending mode or gyroscopic loading conditions, necessitating an improved rotor support system to enhance stability and performance.
Innovation Solution
A rotor support system featuring a bearing assembly with a stationary support frame and a rotatable race, where the rotatable race engages the rotatable drum rotor at discrete, circumferentially spaced locations, utilizing oil-less ceramic bearings for high-speed and high-temperature applications, and optionally submerged in a viscous fluid or grease pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional rotor support systems are used, then the structure is simpler, but the rotor experiences high deflection at free ends during bending mode or gyroscopic loading conditions
Solution Approach 1:
The rotor support system is divided into multiple bearing assemblies, each with discrete bearing locations positioned at different circumferential positions around the rotor. This segmentation allows each bearing assembly to independently support specific portions of the rotor, reducing overall deflection while distributing the structural complexity across modular units rather than requiring a single complex support structure.
Solution Approach 2:
The patent introduces bearing assemblies positioned at multiple circumferential locations around the rotor, transitioning from a single-plane or simple axial support to a multi-dimensional support configuration. This spatial distribution of bearing locations in the circumferential direction provides enhanced stability by supporting the rotor from multiple angular positions, effectively reducing deflection in bending and gyroscopic modes.
2Reliability
If multiple bearing assemblies are used to reduce deflection, then rotor stability improves, but the device complexity increases
Solution Approach 1:
Each bearing assembly is designed to perform multiple functions: supporting radial loads, accommodating thermal expansion, and providing flexibility during rotor rotation. The bearing assemblies use universal joints or flexible connections that allow them to adapt to various operating conditions including thermal growth and bending modes, thereby enhancing reliability without requiring entirely different support mechanisms for each function.
Solution Approach 2:
The bearing assemblies incorporate dynamic elements such as flexible connections and adjustable positioning mechanisms that allow the support system to adapt during rotor operation. This dynamic capability enables the bearing assemblies to maintain optimal support characteristics under varying loading conditions, thermal states, and rotational speeds, improving reliability while avoiding the need for overly rigid and complex fixed support structures.
3Adaptability or versatility
If discrete bearing locations are used, then contact and flexibility are maintained across thermal operating environment, but manufacturing precision requirements increase
Solution Approach 1:
The bearing support system is segmented into multiple discrete bearing assemblies located at different circumferential positions. Each assembly is manufactured and positioned as a separate module, which allows for standardized manufacturing processes and simplified alignment procedures. This segmentation reduces the cumulative precision requirements compared to a single integrated support structure, as each module can be independently manufactured and then assembled with standard tolerances.
Solution Approach 2:
The bearing assemblies incorporate self-aligning features or flexible connections that automatically adjust to thermal expansion and positioning variations during operation. This self-adjustment capability compensates for minor manufacturing tolerances and installation variations, maintaining proper contact and flexibility across the thermal operating environment without requiring extremely tight manufacturing precision for each bearing location.
Data Source
AI summary
A rotor support system for a gas turbine engine includes a rotatable drum rotor and a non-rotatable support casing. The rotor support system includes a bearing assembly configured for positioning between the rotatable drum rotor and the non-rotatable support casing. The bearing assembly includes, at least, a stationary support frame and a rotatable race. Further, the rotatable race is configured to engage the rotatable drum rotor at separate and discrete locations that are circumferentially spaced apart around the rotatable drum rotor.